A dual-signal-amplified photoelectrochemical aptasensor for dual detection of β-lactoglobulin and Ara h1 allergens

Developing a fast, accurate, and simple detection method for food allergens is imperative to prevent food allergy. In this study, an on–off-on photoelectrochemical (PEC) aptasensor with dual-signal amplification was constructed based on a covalent organic frame (COF) film to detect β-lactoglobulin (BLG) and Ara h1. Specifically, a uniform and stable TFTA COF film was in situ grown as a PEC signifier on the surface of an indium tin oxide (ITO) electrode. BLG recognition triggered enzyme-assisted circular signal amplification to introduce non-conductive SiO 2 -modified DNA (S0) to the platform, effectively quenching the PEC signal for ultra-sensitive detection of BLG. Upon adding Ara h1, SiO 2 -DNA was released from the sensing platform to restore the PEC signal, and hemin was added to form a G-quadruplex/hemin compound for secondary signal amplification. Thus, sensitive detections of BLG and Ara h1 were achieved with low detection limits (18 ng/mL for BLG and 2.6 ng/mL for Ara h1) and wide linear ranges (0.05–5 µg/mL for BLG and 0.01–0.2 µg/mL for Ara h1). The dual-amplification and dual-target-responsive PEC aptasensor provides a new idea to develop PEC analysis methods for multi-targets in food and environmental monitoring.